Add a custom linkification filter

Note: This feature can only be controlled by organization administrators.

Linkification filters make it easy to refer to issues or tickets in third
party issue trackers, like GitHub, Salesforce, Zendesk, and others.
For instance, you can add a filter that automatically turns #2468
into a link to https://github.com/zulip/zulip/issues/2468.

From your desktop, click on the gear
() in the upper right corner.

Select Manage organization.

On the left, click Filter settings.

Under Add a new filter, enter a Regular expression and
URL format string.

Click Add filter.

If the pattern appears in a message topic, Zulip can't linkify the topic
itself, since clicking on a topic narrows to that topic. So Zulip
instead provides a little button to the right of the topic that links to
the appropriate URL.

Understanding linkification regular expressions

This is best explained by example.

Hash followed by a number of any length.

Regular expression: #(?P<id>[0-9]+)

URL format string: https://github.com/zulip/zulip/issues/%(id)s

Original text: #2468

Automatically links to: https://github.com/zulip/zulip/issues/2468

String of hexadecimal digits between 7 and 40 characters long.

Regular expression: (?P<id>[0-9a-f]{7,40})

URL format string: https://github.com/zulip/zulip/commit/%(id)s

Original text: abdc123

Automatically links to: https://github.com/zulip/zulip/commit/abcd123

Linkifiers can be very useful, but also complicated to set up. If you have
any trouble setting these up, please email support@zulipchat.com with a few
examples of "Original text" and "Automatically links to" and we'll be happy
to help you out.